Semiconductor package having smart power stage and E-fuse solution

Abstract

A semiconductor package comprises a lead frame, a low side metal-oxide-semiconductor field-effect transistor (MOSFET), an E-fuse MOSFET, a high side MOSFET, a metal connection, a gate driver, an E-fuse IC, and a molding encapsulation. A buck converter comprises a smart power stage (SPS) network and an E-fuse solution network. The SPS network comprises a high side switch, a low side switch, and a gate driver. A drain of the low side switch is coupled to a source of the high side switch via a switch node. The gate driver is coupled to a gate of the high side switch and a gate of the low side switch. The E-fuse solution network comprises a sense resistor, an E-fuse switch, an E-fuse integrated circuit (IC), and an SD circuit.

The invention claimed is: 
     
       1. A buck converter comprising
 a smart power stage (SPS) network comprising
 a high side switch; 
 a low side switch, a drain of the low side switch being coupled to a source of the high side switch via a switch node; and 
 a gate driver coupled to a gate of the high side switch and a gate of the low side switch; and 
 
 an E-fuse solution network comprising
 an E-fuse switch, a source of the E-fuse switch coupled to a drain of the high side switch; 
 an E-fuse integrated circuit (IC) comprising
 a comparator comprising
 a reference input; 
 a functional input coupled to a short detection (SD) node; and 
 an output; and 
 
 
 an SD circuit coupled to the SD node of the E-fuse IC, the SD circuit comprising
 a first circuit resistor, a first node of the first circuit resistor being coupled to the switch node; 
 a second circuit resistor; 
 a circuit capacitor; and 
 a circuit diode. 
 
 
 
     
     
       2. The buck converter of  claim 1 , wherein the low side switch is a first metal-oxide-semiconductor field-effect transistor (MOSFET);
 wherein the high side switch is a second MOSFET; and 
 wherein a size of the first MOSFET is larger than a size of the second MOSFET so that the high side switch has lower peak current handling capacity than the low side switch. 
 
     
     
       3. The buck converter of  claim 2 , wherein the E-fuse IC further comprises an integrated current sense amplifier measuring current through the high side switch; and
 wherein the E-fuse IC turns off the E-fuse switch when the current through the high side switch is larger than a pre-determined value. 
 
     
     
       4. The buck converter of  claim 3 , wherein the E-fuse IC monitors an on resistance of the E-Fuse switch to estimate current through the high side switch. 
     
     
       5. The buck converter of  claim 3 , wherein the E-fuse solution network further comprising a sense resistor and the current sense amplifier detects a voltage drop across the sense resistor to measure the current through the high side switch. 
     
     
       6. The buck converter of  claim 3 , wherein the E-fuse switch comprises a trench MOSFET with a second mirror FET integrated as common drain MOSFETs. 
     
     
       7. The buck converter of  claim 3 , wherein the current through the high side switch increases when the high side switch is short and the gate driver continues to drive the low side switch. 
     
     
       8. The buck converter of  claim 1 , wherein the SD circuit measures a time duration when the switch node stays high;
 wherein a value of the functional input corresponds to the time duration when the switch node stays high; 
 wherein the output of the comparator flags a fault signal when the value of the functional input is larger than a value of the reference input. 
 
     
     
       9. The buck converter of  claim 8 , wherein the time duration increases when the high side switch is short and the low side switch is not turned on.